The characteristics of effective research questions include:
- must be focused: Effective research questions should target a specific issue or area of inquiry.
- must be answerable: The questions should be formulated in a way that allows for an answer based on research and analysis.
- must be clear: The questions need to be understandable and unambiguous.
- must be specific: They should be detailed enough to guide the research process and provide a clear direction.
Therefore, the correct characteristics from your list are: focused, answerable, clear, and specific.
The options "must be broad" and "must include a quotation" are not characteristics of effective research questions. Generally, research questions should not be too broad, as this can make them difficult to address adequately. Including a quotation is not a requirement for formulating effective research questions.